March 2021*

A 55 year old female with expanding gluteal mass

Contributors: 

Bianca Puello Yocum, MD

PGY 2

Department of Pathology and Laboratory Medicine

Indiana University School of Medicine

Romil Saxena, MD, MBBS, FRCPath

Professor of Pathology & Laboratory Medicine

Professor of Medicine

Director, Fellowship in Gastrointestinal Pathology

Department of Pathology and Laboratory Medicine

Indiana University School of Medicine

*This case has been peer reviewed

Clinical history:

A 55 year old female presented with an enlarging, painful gluteal mass for 1 month. The patient was otherwise asymptomatic with vital signs and laboratory tests within normal limits; in particular, there were no symptoms or signs of infection. Her medical history included cirrhosis due to alcohol abuse, obesity, bipolar disorder, asthma, a 10 pack years smoking history, and recent cholecystectomy. She was not on any immunosuppressive therapy. On examination, there was a 5x5 cm fluctuant mass with surrounding induration and red streaking. MRI showed an enhancing mass in the subcutaneous tissue with stranding at the periphery, thought to represent an abscess or necrotizing sarcoma. An incision and drainage was performed, which yielded 250 cc of purulent fluid. Wound culture of the fluid grew E. coli. Due to persistent pain after the initial procedure, approximately 3 weeks later the patient was taken to the operating room for additional incision and drainage under general anesthesia. A sample of the surrounding tissue was sent for histologic examination.

Gross examination:

The specimen consisted of a 6.5 X 5.5 X 2.5 cm portion of fibro-adipose tissue surfaced by skin. Sectioning the specimen showed a tan-white, firm, cystic and solid mass.

Microscopic examination and immunohistochemistry:

Sections showed a fibro-inflammatory mass involving the subcutaneous fibro-connective tissue. It consisted of sheets of histiocytes and plasma cells with intermingled lymphocytes. Present within the inflammatory infiltrate were histiocytes containing small basophilic inclusions, consistent with Michaelis-Gutmann bodies. These structures stained for calcium and iron by the von Kossa and Prussian blue stains, respectively. Areas of hyalinization were present within the inflammatory mass. Special stains for micro-organisms were not performed.

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Fig. 1:  Fibro-inflammatory mass made up of plasma cells and sheets of spindled or epithelioid histiocytes with a granulomatous appearance. (H&E 100x)

 Fig. 1     

Fig. 2: High power view demonstrating abundant macrophages along with several scattered spherical, calcified intracellular inclusions, Michaelis-Gutmann bodies (H&E 200x)

 Fig. 2

Fig. 3: Periodic acid-Schiff highlighting von Hansemann cells (400x)

 Fig. 3

Fig.4:   von Kossa stain highlighting numerous Michaelis-Gutmann bodies (200x)

Fig.  4

March 2021 Final Diagnosis and Discussion